I have to say that I am having fun with your gravity simulator. It is by far the best one that I have seen. However I have a few quick suggestions for future improvements.

Fist off let me explain what I am trying to do. I am creating a system for another project and trying to figure out if the system I am developing is stable. You can see my system at http://www.shatters.net/forum/viewtopic.php?t=2448. Anyway inside my system I have a planet with ~8 Jupiter masses in size. However I am not sure how close in I can get the planet to the central star without disabling the other planets inside the system. I am using the Gravity Simulator to answer this question.

Back to the improvements.

One thing I have come to love to hate is when you go to enter an object, you enter with the standard Newton orbital elements, but when you go to edit the object you are give vector locations. This is fine if you know what you are doing, but when it comes to simple moving a planet out a few AU and wanting to recalculate the rotational speed, it is kind of depressing because now I have to reenter all the original data. So I guess what I am getting at is it would be nice to store the original data and modify that instead of having to end the vector information. This also allows one to simply edit the original system and restart the system from day one.

Next I think it would be nice to add fading tails so as the object pass it leaves a tail that gradually gets darker. This way you can always see where the object is no matter how many orbits it has made.

Finally when it comes to the selection of objects, it would be nice to see a tree view of objects all listed based upon distance and not upon what item was entered first.

One thing I have come to love to hate is when you go to enter an object, you enter with the standard Newton orbital elements, but when you go to edit the object you are give vector locations.

I think that' annoying too. I don't know when I'll release an update, but I plan on combining those features. The fading trails is something I've already toyed with before releasing the current version, but I didn't like my effort. Maybe next time too.

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from Celestia I find it amusing that the Rylix system is more stable then the Sol System according to the program. Go figure.

You may be using too large of a time step. Sol's system should be quite stable.

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from Celestia I think I need to adjust the orbits slightly so they are more circular and have approximately the same ascending nodes (right now they are more or less random)

Your ascending nodes should be random. Sol's are. They precess over time, so they would become random even if you set them the same to begin with.

Re: A few quick suggestions for future release.Reply #2 - 01/04/06 at 22:20:28

Thanks, for the reply.

It is turning out that the names are the easiest part of system development. When I originally created my system I more or less just came up with a planet, gave it a mass and assigned a distance. Well itís turning out that the masses of the planet are killing the system, so to stabilize it I have to move the orbits around. One object in particular, Gigus, is throwing everything off. The mass is so huge that it throws objects into a tizzy. Some objects are stable but others go wacko. I updated the Celestia page if you want to see my results.

For my next test, I am going to use my original, original number just to see what will happen. I know that Gigus and Hyperion will not get along to well, there is just too much gravitational pressure between the two, but if the orbit oscillates and is stable I might stay with my original numbers for the inner system. This will give me more room to play on the outside. I was tying to keep the entire system under 50AU.

Also I though of another feature you might want to add.

I noticed that when rendering you render to the video buffer and then donít clear it bfore generating the next plot point. This is a simple yet effective way of rendering a path. However soon as you rotate the image, you loose all the rendering data. It would be cool if you could keep a history of this data, and I think that the easiest way would be to save to a file every ďnthĒ plot point then to generate the path back you recall and render those plot points saved in the file. This would also alloy you to zoom in and out without loosing the paths. You could add a time stamp to this feature so you could render over night and then in the morning play back the entire system if fast forward and not have to worry about the accuracy, and play back events. Granted this would take a lot of disk space, but I think it would be worth it just to see a planet or moon gets flung out of the system, and be able to repeat it.

-Matt-

P.S. I am using a time increment of 1024sec now and the system seems to have stabilized without eject planets.

One thing I'd like to see is the option of being able to enter an object's orbital period around another object and having the system automatically create the distance for you. Right now, I'm working on a simulation where I know how long I want the planets to take to orbit the parent star but don't know the correct distance that matches the desired orbital periods. Having the option of entering orbital period would be ideal in a situation like this. Later!

If your planets are orbiting the Sun, simply type "1 Ms" for mass. If you'd like to express your time in years, just type "yr" after your value. If you would like your computed SMA to be in AU, highlight the "m" following the computed value and type "a".

Re: A few quick suggestions for future release.Reply #5 - 05/13/06 at 04:52:30

very nice system there... although i do think the spaces between the outer and larger planets are too small for stable obits past a few million years.... The bigger the planet the more space it needs to be safe?

i like the program you used to make the solar system nice and colourful, but it looks complex. How easy was it to get into?